As Slate nerdily notes (and I, also nerdily, find to be a good application of the collective action problem), more bracelets do not necessarily mean more awareness:
Perhaps you're familiar with "the tragedy of the commons," a social dilemma outlined by the late biologist Garrett Hardin in a famous 1968 essay of the same name. The dilemma is that when individuals pursue personal gain, the net result for society as a whole may be impoverishment. (Pollution is the most familiar example.) Such thinking has fallen out of fashion amid President Bush's talk of an "ownership society," but its logic is unassailable:
Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. … As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks, "What is the utility to me of adding one more animal to my herd?" This utility has one negative and one positive component.
1) The positive component is a function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly +1.
2) The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision-making herdsman is only a fraction of -1.
Adding together the component partial utilities, the rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another; and another …
The same logic applies to awareness bracelets. In this instance, the "common" is the visible spectrum, and the "herdsmen" are the groups promoting various causes by selling awareness bracelets of various colors. The problem is that there are only so many colors, while the number of causes is nearly infinite. At this late hour, it's impossible to look at somebody's awareness bracelet and learn precisely what that person is trying to raise awareness about, because there are simply too many possibilities. Purple, for instance, now signifies support for Alzheimer patients, abused animals, battered women, epileptics, children in foster care, or people with irritable bowel syndrome, among other things. Teal invokes the fight against ovarian cancer, except when it invokes the fight against myasthenia gravis, drug addiction, or sexual assault. Gray can raise awareness about brain cancer, diabetes, disabled children, emphysema, lung cancer, multiple sclerosis, mental illness, or a couple of diseases I've never heard of; or it can raise awareness about asthma or allergies. ("Please join me in the fight to cure hay fever.")